Over-the-road vehicles such as tractor-trailer combination vehicles are used in moving significant amounts of freight from site to site, whether over long distances or short distances. This freight includes manufactured goods, food items, live animals, etc., with most freight collectively being of heavy weight and therefore requiring tedious work in its loading and unloading to and from a transporting trailer.
One particular area where loading and unloading presents vulnerability to cargo involves the transporting of livestock, and particularly horses. Specifically, and as opposed to being freight that can be hand carried, live animals must propel themselves into and out of the shipment trailer. Consequently, specialized attendants must be present to guide the animals along temporary ramps leading from the ground to the trailer. If an animal should lose its footing and fall from such a ramp, fractured bones and possible animal loss is possible.
In view of the inconvenience and potential accidents associated with the required use of ramps in the loading of shipment trailers, it is apparent that a need is present for safer, more direct access to the trailers. Accordingly, a primary object of the present invention is to provide a retractable and extendable wheel assembly for mounting to a vehicle such that the vehicle can be lowered for loading and unloading.
Another object of the present invention is to provide such a retractable and extendable wheel assembly wherein expandability and retractability is accomplished through inflation and deflation of an air ram integral with the wheel assembly.
Yet another object of the present invention is to provide such a retractable and extendable wheel assembly wherein a pivotally mounted support strut operates in cooperation with the air ram to support the wheel in place and guide its vertical movement during inflation and deflation of the air ram.
These and other objects of the present invention will become apparent throughout the description thereof which now follows.